Fix string parser

[Niuslar]

After running the tests I noticed some cases where the parser would pass the command to the controllers even when the format should be invalid. There's also a case that breaks the whole application.

Here's a summary of the failed tests:

Command tested	Expected Result	Result	Possible reason
>temperature(arg1, arg2, arg3, ... arg20) [20 values]	Malformat	Break the app or OK.	There's no argument limit check in the parser and it's writing into m_arguments beyond its limit
>temperature(asd25)	Malformat	Not recognised	I think the parser takes that as a string argument
>temperature(1,2,,,,,3,4,5,6,7,8,9,0)	Malformat	OK.	I think the parser is storing empty values as arguments?

Also here's a list of all the commands I tried and their expected results, let me know if you want me to add/change any.

Command	Expected Result
>?temperature()	COMMAND_OK
>temperature(25)	COMMAND_OK
command_00	COMMAND_MALFORMAT
>>temperature(asd25)	COMMAND_MALFORMAT OK
temperature(25)	COMMAND_MALFORMAT
>temperature(1,2,3,4,5,6,7,8,9,0)	COMMAND_OK
>temperature(1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0)	COMMAND_MALFORMAT
>temperature(1,,,2,3,4,5,6,7,8,9,0)	COMMAND_MALFORMAT
>temperature25)	COMMAND_MALFORMAT
>temperature(25	COMMAND_MALFORMAT
>temperature(25 24 21 53)	COMMAND_MALFORMAT